Safety relief valve



Patented Apr. 8, 1924.

UNITED STATES lATENT OFFICE..

AXEL E. ERICKSON, OE CHICAGO, ILLINOIS, AssIeNon OE ONE-THIRD To MILESC. sT. JOHN, OE CHICAGO, ILLINOIS.

SAFETY RELIEF vAILvE.

Application led August 19, 1922. Serial No. 582,871.

VSafety Relief Valve; and I do hereby declare that the following is afull, clear, and

exact description of the same, reference being had to the accompanyingdrawings, and

tothey numerals of reference marked there-V on, which form a part ofthis speciiication.

This invention relates to safety or relief valves for high pressurevessels wherein a minimum loss of the contents is desirable for anyreason. It has special reference to safety valves for vessels containingexpensive or dangerous liquids or gases, such, for example, as ammoniarefrigerating systems wherein a loss of the refrigerant means not onlythe release of a dangerous gas but a waste of expensive material.

Heretofore the safety valves used on such special installations haveborne a strong resemblance to the ordinary pop safety valves used onsteam boilers. Such valves necessarily open at one pressure, which isadjustable to the individual requirements, and close at a much lowerpressure, thus blowing oil" a considerable quantity of steam in the caseof boilers. With many high pressure processes, as, for example,refrigerating systems, such a loss of liquids or gases must be avoidedas far as possible.

It is an important object of this inven tion to construct a pressurereliefvalve that will open at a predetermined pressure and close afteronly a very slight drop in pressure thus conserving the contents of thevessel.- v

It is a further important object of this invention to `provide 'a quickseatingl balanced relief valve having a very small range between theopening and closing pressures.

It is still a further important object of this invention to provide aby-passed relief valve wherein when said valve is open, the sum of thespring `pressure and the fluid pressure on the top of the valve will besuiiicient to close said valve after a very slight drop in pressurewithin the pressure vessel.

Another important object of this invention is to provide a self-seatingvalve that will seat securely even after long usage.

A further important object of this inveneasily adjusted,

tion is to provide a simple,

and cheaply manufactured relief easily valve.

Other `and further important objects of this invention will be apparentfrom the disclosures in the specilicationand the accompanying drawings.

The invention (in a preferred form) is illustrated in the drawings andhereinafter more fully described. v

Onl the drawings:

Figure 1 is an elevation of a preferred form of a device embodying thisinvention.

Figure 2 is a top plan view of this device.

Figure 3 is a sectionon the center line of Fig. 1.

Figure 4 is a section on the line 4-4 of Figure 3.

As shown on the drawings;

The preferred form of this invention comprises a substantiallycylindrical body designated by the numeral 1 having a cylindri- Cal boretherethrough of varyingdiameters. The bottom of the body 1 is tapped at2 to receive a pipe connection 3 leading to a pressure vessel (notshown). Just above this pipe the body is internally threaded at 4 toreceive a shouldered and passaged relatively soft metal bushing 5 whichserves as a renewable valve seat. The shoulder 6 on this bushing seatson a shoulder 7 within the body central bore. About midway of the body afurther enlargement 9 of the borevserves to locate a shouldered bushinglO'which is securely pressed into place. The upper end of formed by anvenlargement 8 of the the enlargement 9 is internally threaded at A 11for a shouldered plug 12 which is locked in place by a lock-nut 13.Centrally disposed in said plug 12 is an adjustable conel pointed setscrew 14 held in adjusted position by a lockY nut 15. A cover 16 isthreaded onto the shoulder 17 of the plug 12 to conceal the set screw14.

The valve mechanism comprises only two moving parts and a spring, andconsists ofY a cup pointed cylindrical valve 18 having a good slidinglit in the bushing 10 and is prevented from turning therein by a pin 19Y exterior form can be used, thus eliminating the use of a pin toprevent turning of the valve. f

The valve body 18 is receive the end of a spring seat 23 having acentering boss 24 for a coil spring 25 which is held at its upper end bya spring washer 26 having a similar boss 27. As shown, the valve body isinternally threaded but this is for ease of handling during machiningand has no function in the completed valve.

An outlet pipe connection 28 is tapped into the side of the body 1 andcommunicates with the valve recess 22 through the registering apertures29 in the bushing 10 and 30 in the valve body 18.

The operation is as follows:

ln use this valve is connected to a pressure vessel by means of the pipe3 and the pressure within the vessel gradually brought up to theallowable limit at the same time adjusting the set screw 11i until thespring pressure will yield and allow the valve to open at the requiredpressure. lifter securing the proper adjustment, the set screw is lockedin position by means of the loch nut l5 and the cover 16 applied to theplug 12.

An increase in pressure beyond the limit the valve is adjusted to holdcauses a lift of the valve 18 against the action of the spring and partof the fluid or'gas within the pressure vessel passes the valve 18through the passage formed by the flat 21 on the side of the valve andinto the spring chamber above the valve, thence into the interior recess22 of the valve 1S and is discharged through the apertures and 29 intothe pipe 28 which forms a vent leading to a distant discharging point inthe case of apparatus containing a liquid which yields eX- plosive ornoxious vapors.

lt will thus be seen that with the valve 18 lifted, substantiallyuniform pressure exists above and below the valve, thus permit-ting thespring 25 to reseat the valve. In operation this valve would rapidlyflutter rather than beheld open until the pressure within the vessel wasreduced to a considerable eX- tent,`as would be the case with anordinary pop Ysafety valve.

By making the renewable valve seat of a relatively softer material thanthe valve, the

recessed as at 22 to valve forms its own seat and securely seals theopening anew eac-h time the valve comes down. lilith refrigeratingmachines, for e-X- ample, this is an important feature, as the valve isset" te'release at pressures considerably above the. normal operatingpressures and consequently the valve may stand unused for long periodsof time, yet it must seat perfectly after blowing off.

l am awa c that numerous details of construction n ry be varied througha wide range without departing from the principles of this invention,and l therefore do not purpose limiting the patent granted otherwisethan necessitated by the prior art.

l claim as inv invention: 1. il. safety cf valve, comprising a hollowbody having an inlet connection, a valve seat therein, aspring-controlled valve therefor, a constantly open lay-pass from saidvalve seat around said valve, and an outlet connection in said bodycommunicating with the side of said valve opposite to said inletconnection.

2. :i safety relief valve, comprising a hollow body having an inletconnection, a valve seat therein, a. spring-controlled valve thereforformed hollow and open at its end opposite said valve seat, a. by-passfrom said valve seat to said open end of the valve, and a lateral outletconnection communicating with the interior of said valve.

ifi safety relief valve, comprising a hollow body having an inletconnection, a valve seat therein, a valve therefor formed hollow andopen at its end opposite said valve seat, a by-pass from said valve seatto said open end of the valve, a spring seat comprising a centering bossloosely disposed in said valve, a spring bearing on said spring seat,means for adjusting the tension of said spring, and an outlet connectioncommunicating with the interior of said valve through alined openings.

ln testimony whereof l have hereunto subscribed my name in the presenceof two subscribing witnesses.

AXEL F. ERLCKSON.

Witnesses:

CARLTON HILL, Minis C. ST. JOHN.

